The present invention relates to device for detect very high data rate digital subscriber line (VDSL) signal and more particularly to a mobile VDSL signal detector with improved characteristics.
In recent years, the Internet has been widely employed worldwide. Particularly, the World Wide Web (WWW) can provide voice, graphics, and multimedia services in addition to e-mail transmission and receiving. As such, people can retrieve information from millions of sources. A conventional modem can only provide a transmission speed of 28.8, 33.6, or 56 kbps over a typical telephone line. Moreover, local area network (LAN) or even integrated service digital network (ISDN) cannot provide a transmission speed up to that of the Internet. Hence, more and more people are not satisfied with the above LAN and ISDN techniques. For accommodating the coming of multimedia which requires very large data, many Internet service providers (ISPs) propose solutions about high speed data transmission for users. Currently, digital subscriber line (DSL) is the most important one of the solutions. Intuitively, DSL is a digital telephone line rather than conventional plain old telephone service (POTS) which is analog in nature. DSL has many versions which are commonly called xDSL. In the DSL based systems, VDSL is the most important one. VDSL can transmit data over exiting POTS without additional equipment. Hence, VDSL can effect a faster data transmission, high transmission efficiency, and a great convenience to our daily life and work.
Also, VDSL is the fastest one among xDSLs. VDSL can provide a data transmission rate at a range between 12.9 Mbps and 52.8 Mbps or even up to 60 Mbps over a twisted pair wire. Note that transmission rate of VDSL varies depending on length of telephone line. VDSL can be symmetric or asymmetric. Transmission medium employed by VDSL based system is established on a copper wire based telephone line. Hence, a known telephone line (i.e., dial tone based one) can transmit a high data rate without altering the existing telephone line. In other words, VDSL is capable of not only providing a high speed data transmission but also maintaining the functions of known telephone line without being equipped with a telecommunication device of central office (CO). This configuration is best illustrated in FIG. 1. In the VDSL based system 1, a VDSL modem 30 is coupled to telecommunication device 10 of CO and a VDSL modem 40 is coupled to a user device 20 respectively. VDSL modems 30, 40 employ a bandwidth larger than that of voice so as to transmit data in high speed.
Moreover, telecommunication device 10 of CO is coupled to user device 20 via the known telephone line 50. A conventional analog telephone set is replaced by VDSL modem 40 coupled to user device 20. Hence, VDSL modem 40 has the function of the know telephone. A lower bandwidth portion of VDSL is utilized in the conventional telephone service. Such lower bandwidth portion is utilized by a POTS splitter 41 of VDSL modem 40 in a passive filtering so as to separate POTS signals from the lower bandwidth portion. The remaining bandwidth is utilized to transmit data.
VDSL modem 30 in CO has to modulate or encode data transmitted from ISP and Internet access signal transmitted from a telephone company or data transmitted from a network company into a VDSL signal. Further, VDSL signal is combined with POTS signal prior to transmitting to user device 20 over the known telephone line 50. Also, POTS splitter 41 of VDSL modem 40 in user device 20 can separate digital signal from POTS signal. The digital signal is in turn decoded or demodulated in ATU-R device 42. Finally, decoded or demodulated signal is transmitted to a device (e.g., computer) of user device 20. In a reverse transmission path, data from device of user device 20 is transmitted to VDSL modem 40 of user device 20 in which digital signal to be transmitted is encoded or modulated in ATU-C device 32. Then the encoded or modulated signal is combined with POTS signal having lower bandwidth prior to transmitting to CO. At CO, POTS splitter 31 of VDSL modem 30 can separate POTS signal from digital signal. Hence, digital signal to be transmitted is decoded or demodulated prior to transmitting to ISPs, Internet users, or Intranet.
In nature, VDSL is an all weather digital line without interfering voice channel. In other words, user can access VDSL data and make a call over known telephone line at the same time. That is why it becomes more and more popular among consumers. For accommodating such trend, many telecommunication service providers install additional communication devices for providing VDSL bandwidth services. This not only greatly increases data communication efficiency but also brings a great market to the art.
In above VDSL configuration, in the case that line interruption between telecommunication device of CO 10 and user device 20 or poor communication quality occurred, typically a service person has to carry a bulky computer and associated VDSL modem to the site of each node of the line for simulating telecommunication device of CO 10 or user device 20. In the simulation a packet is sent to telecommunication device of CO 10 or user device 20 for test. Then a determination is made as to whether a reply packet is sent back from user device 20 or telecommunication device of CO 10. This determination can assure that whether there is a line interruption between telecommunication device of CO 10 and user device 20 or the communication quality is poor. Such test technique is completely different from that performed on the conventional analog telephone line. Hence, service personnel are required to have a through network knowledge as well as the strength to carry a bulky computer and associated VDSL modem to the site of each node of the line for test. As such, an appropriate power source is required to install in each node of the line for supplying power for normal operation. In view of above, the test is very complicated and difficult. Moreover, very few service personnel of the telephone company can take this job since they are only familiar with repair of the conventional analog telephone line. Thus, a need exists in VDSL based wide bandwidth network system for providing a good communication quality while expanding the existing telephone line in the art.
It is desirable to provide a mobile VDSL signal detector. In use, a service person of a telephone company can bring the detector to a location along a telephone line coupled between a telecommunication device of CO and user devices for test so as to quickly find out the cause of a malfunction.
In one aspect of the present invention, the detector comprises a microprocessor so that when a test item is inputted through an input device, the microprocessor is activated to read the test item. Then an identification (ID) of a user device or telecommunication device of CO corresponding to the test item is written into a VDSL chipset of the detector. In VDSL chipset, a virtual user device or telecommunication device of CO is simulated. Next, send a packet to telecommunication device of CO or user device for test. Finally, a determination is made as to whether there is a line interruption between telecommunication device of CO and user device or the communication quality is poor based on a strength of a signal sent back from the telecommunication device of the CO or the user device. By doing this, it is possible of quickly finding out a malfunction occurred on the telephone line between telecommunication device of CO and user devices.
In another aspect of the present invention, the detector comprises a backup source for supplying power for normal operation of the detector. In use, a test person can carry the detector for checking the telephone line without having to carry an additional adaptor connectable to an external power source.
In a further aspect of the present invention, the detector comprises a set of indicators for showing test result for test person""s visual reference. Hence, test person can quickly find out a malfunction occurred on the telephone line between telecommunication device of CO and user devices. Most importantly, the malfunction can be quickly solved, thus increasing communication efficiency and quality.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.